This paper presents a novel approach to creating optically reconfigurable photonic devices using phase change materials (PCMs). The researchers demonstrate a dielectric metasurface that can be written, erased, and rewritten with light in a non-volatile and reversible manner. The metasurface is created using a sub-wavelength resolution optical writing process on a nanoscale film of Ge2Sb2Te5 (GST), a phase change material known for its thermal stability and high switching speed. By inducing a refractive index-changing phase transition with tailored femtosecond laser pulses, the researchers achieve dynamic control of optical properties with diffraction-limited resolution and in a femtosecond time-frame. The study demonstrates various photonic devices, including reconfigurable bi-chromatic and multi-focus Fresnel zone-plates, a super-oscillatory lens with sub-wavelength focus, a grey-scale hologram, and a dielectric metamaterial with on-demand reflection and transmission resonances. The devices are written, erased, and rewritten using a sub-wavelength resolution optical-pattern generator/imaging system with a spatial light modulator and femtosecond laser source. The system achieves a resolution of 0.59 μm and allows for the creation of various photonic functions that are difficult or impossible with conventional technologies. The researchers also show that the GST film can sustain a large number of transition cycles between amorphous and crystalline states, making it suitable for reconfigurable photonic devices. The technology allows for the creation of dynamic diffraction gratings, switchable frequency selective surfaces, reflectors, light diffusers, and scatters, as well as non-volatile reconfigurable spatial light modulators and signal distributors. The study highlights the potential of this technology for applications in on-chip applications, space division multiplexing in telecommunication networks, and adaptive optics. The paper also discusses the advantages of using phase change materials for reconfigurable photonic devices, including their ability to provide high spatial resolution, fast switching speeds, and the potential for integration with existing optical technologies. The study concludes that this technology offers a versatile platform for creating dynamically reconfigurable optical devices that can be reconfigured with light, with potential applications in a wide range of optical and photonic systems.This paper presents a novel approach to creating optically reconfigurable photonic devices using phase change materials (PCMs). The researchers demonstrate a dielectric metasurface that can be written, erased, and rewritten with light in a non-volatile and reversible manner. The metasurface is created using a sub-wavelength resolution optical writing process on a nanoscale film of Ge2Sb2Te5 (GST), a phase change material known for its thermal stability and high switching speed. By inducing a refractive index-changing phase transition with tailored femtosecond laser pulses, the researchers achieve dynamic control of optical properties with diffraction-limited resolution and in a femtosecond time-frame. The study demonstrates various photonic devices, including reconfigurable bi-chromatic and multi-focus Fresnel zone-plates, a super-oscillatory lens with sub-wavelength focus, a grey-scale hologram, and a dielectric metamaterial with on-demand reflection and transmission resonances. The devices are written, erased, and rewritten using a sub-wavelength resolution optical-pattern generator/imaging system with a spatial light modulator and femtosecond laser source. The system achieves a resolution of 0.59 μm and allows for the creation of various photonic functions that are difficult or impossible with conventional technologies. The researchers also show that the GST film can sustain a large number of transition cycles between amorphous and crystalline states, making it suitable for reconfigurable photonic devices. The technology allows for the creation of dynamic diffraction gratings, switchable frequency selective surfaces, reflectors, light diffusers, and scatters, as well as non-volatile reconfigurable spatial light modulators and signal distributors. The study highlights the potential of this technology for applications in on-chip applications, space division multiplexing in telecommunication networks, and adaptive optics. The paper also discusses the advantages of using phase change materials for reconfigurable photonic devices, including their ability to provide high spatial resolution, fast switching speeds, and the potential for integration with existing optical technologies. The study concludes that this technology offers a versatile platform for creating dynamically reconfigurable optical devices that can be reconfigured with light, with potential applications in a wide range of optical and photonic systems.